Identify each variable as discrete or continuous:
a) Population of each country represented by HL students in your session of the exam.
b) Weight of IB Maths HL exams printed every May since 1976
c) Time it takes to mark an exam paper by an examiner.
d) Number of customers served at a bank counter.
e) Time it takes to finish a transaction at a bank counter.
f) Amount of sugar used in preparing your favourite cake.